#include <iostream>
using namespace std;

int bin(int n, int k)
{
	if (n < k)
	{
		return 0;
	}
	int k_sum = 1;
	int k_tmp = k;
	while (k_tmp >= 1)
	{
		k_sum = k_tmp * k_sum;
		k_tmp--;
	}
	int n_tmp = n;
	int n_sum = 1;
	while (n_tmp >= 1)
	{
		n_sum = n_tmp * n_sum;
		n_tmp--;
	}
	int x = n - k;
	int sum = 1;

	while (x >= 1)
	{
		sum = sum * x;
		x--;
	}
	return n_sum * k_sum / sum;
}
int main()
{
	int n = 0, k = 0;
	cin >> n >> k;
	cout << bin(n, k) << endl;
}